Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932584AbVISTEg (ORCPT ); Mon, 19 Sep 2005 15:04:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932586AbVISTEg (ORCPT ); Mon, 19 Sep 2005 15:04:36 -0400 Received: from ns1.coraid.com ([65.14.39.133]:27114 "EHLO coraid.com") by vger.kernel.org with ESMTP id S932584AbVISTEf (ORCPT ); Mon, 19 Sep 2005 15:04:35 -0400 To: "David S. Miller" Cc: linux-kernel@vger.kernel.org, jmacbaine@gmail.com Subject: Re: aoe fails on sparc64 References: <87u0glxhfw.fsf@coraid.com> <20050916.163554.79765706.davem@davemloft.net> <87slw1b0fz.fsf@coraid.com> <20050919.112159.55767801.davem@davemloft.net> From: Ed L Cashin Date: Mon, 19 Sep 2005 14:38:26 -0400 In-Reply-To: <20050919.112159.55767801.davem@davemloft.net> (David S. Miller's message of "Mon, 19 Sep 2005 11:21:59 -0700 (PDT)") Message-ID: <877jdc2999.fsf@coraid.com> User-Agent: Gnus/5.110002 (No Gnus v0.2) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1335 Lines: 34 "David S. Miller" writes: > From: Ed L Cashin > Date: Mon, 19 Sep 2005 10:24:00 -0400 > >> 1) Passing le64_to_cpup an unaligned pointer is "OK" and within the >> intended use of the function. I'm having trouble finding whether >> this is documented somewhere. >> >> 2) These new changes to the sparc64 unaligned access fault handling >> will make it OK to leave the aoe driver the way it is in the >> mainline kernel. > > Both #1 and #2 are true. That's interesting. I think I'll send a patch documenting #1. > Although it's very much discouraged to dereference unaligned pointers, > especially in performance critical code (which this AOE case is not, > thankfully), because performance will be really bad as the trap > handler has to fix up the access on RISC platforms. Yes, this only happens when per AoE device when the AoE device is discovered. Still, I might submit a patch that reverts the aoe driver to getting the ATA identify values byte by byte as it used to do. -- Ed L Cashin - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/